The present invention relates generally to billboard video display systems and, more particularly, to a billboard video display system using cathode ray tubes to form the picture elements of the video presentation.
Billboard video display systems are frequently utilized in sporting arenas to provide a large video presentation for viewing by the attending patrons and may also be used on road signs, in shopping centers and the like to display selected video information. For example, systems of this type used in sporting arenas typically provide a video display system screen measuring about 20 by 30 feet, the screen being operated in response to monitor cameras and video tape recorders for displaying instant replays of the sporting event, close-ups of key players and information on other sporting events as well as various news items and commercial messages.
In the past, monochrome video billboard display system screens have been provided by forming an X-Y matrix of incandescent light bulbs, typically 40 watt bulbs, each bulb being individually controllable and representing a single pixel (picture element) of the composite video image formed on the screen. In such a system, each of the pixels of incandescent bulbs is updated at a rate of approximately 50-60 Hz in order to provide a dynamic video image with a minimum amount of flicker. Attempts have been made to upgrade these systems for providing color billboard video displays by using colored bulbs but these attempts have been largely unsatisfactory due to the inefficiency of the color bulbs. In order to overcome this problem, video display system screens have been provided which comprise an arrangement of a plurality of small, usually about one inch in diameter, cathode ray tubes, the screen of each of the cathode ray tubes being flooded by a diverging electron beam for displaying a single color, normally red, green or blue. While the use of such cathode ray tubes is relatively costly, they are considerably more efficient than incandescent bulbs and therefore provide an acceptable color video display. The flood-operated cathode ray tubes are commonly arranged in groups of four to provide a single color pixel. That is, for example, a single color pixel may be formed by arranging four of the tubes in a square matrix with two green tubes being disposed at the opposite corners of one diagonal of the matrix and a red and a blue tube being disposed at the opposite corners of the other diagonal of the matrix. Therefore, the color pixel matrix may be selectively operated for providing a green picture element by flooding the green tubes, a red picture element by flooding the red tube or a blue picture element by flooding the blue tube. Of course, a composite billboard video display picture can be produced by selectively operating a plurality of such color pixel matrices. While a system of this general type provides an adequate billboard color video display picture, the complexity associated with the wiring and mounting hardware needed to accommodate the large number of tubes that are required detracts from the desirability of the system. In addition, in order to achieve adequate resolution, the tubes must be arranged in a relatively tightly packed configuration further increasing the complexity of the system.
It is therefore a basic object of the present invention to provide an improved billboard video color display system.
It is a further object of the invention to provide an improved billboard video color display system wherein the system screen is composed of a plurality of cathode ray tubes each being adapted for providing more than one color picture element.
It is another object of the invention to provide an improved billboard video color display system wherein the system screen is composed of a plurality of cathode ray tubes each of which is scanned by an electron beam for providing more than one color picture element.
It is yet another object of the invention to provide an improved billboard video color display system using a relatively non-complex mounting hardware and wiring system and an electronics package to drive each of a plurality of cathode ray tubes in a scanned mode for providing more than one color picture element.